1. Field of the Invention
The present invention relates to an image display device, and more particularly to an image display device capable of supporting brightness enhancement and power control and a method thereof, which can enhance the brightness and contrast of an image and control the power of a light source in accordance with the image characteristic.
2. Description of the Related Art
Information that is provided to a user through an image display device includes various kinds of multimedia contents as well as simple text information. Examples of the multimedia contents include still images, moving images, sound, and others. Among these multimedia contents, moving images are widely used in video on demand (VOD) services or interactive services. As such, researches on the standards for moving images are being actively carried out.
With the developments in the digital electronic engineering and technology, it is now common for analog data to be digitalized. Accordingly, various digital image processing technologies have been developed to efficiently process large amounts of digital data. The digital image processing technologies have the following advantages.
Generally, unwanted noise which often occurs when analog signals are processed by analog image devices, causing eventual degradation in the processed analog signals, can be prevented in the digital image processing devices.
Further, since digital signals can be processed by a computer, it is possible to perform various kinds of image processing such as image data compression.
At present, most of the digital image display devices such as liquid crystal displays (LCD), plasma display panels (PDP), and organic light-emitting diodes (OLED) adopt an RGB color model.
The color model (or color space) is used to obtain the correlation between any one color and other colors. Different image processing systems use different color models for their respective different reasons. The RGB color model is composed of the three primary colors of red (R), green (G), and blue (B). Spectral components of these colors are added to one another to form additional colors.
The RGB model has a three-dimensional cube having three axes that represent red, green and blue, respectively. The origin of the axes is expressed by black, and the opposite end of the cube is expressed by white. For example, in a 24-bit color graphic system having 8 bits per color channel, red is expressed as (255,0,0).
The RGB model allows a simple design of a computer graphic system. However, the RGB model is not ideal for all applications. This is because the correlation between color components red, green and blue is considerably high. Image processing technologies such as a histogram equalization process images using only brightness. Thus, it is necessary to frequently convert the RGB images into brightness images. To convert the images from RGB colors into brightness level, a value obtained by multiplying each component by ⅓, i.e., an average value is used. Alternatively, Equation (1) may be used in accordance with the National Television Systems Committee (NTSC) Standard.Y=0.288R+0.587G+0.114B  (1)
The technology field relating to techniques for enhancing the brightness and contrast of images in an image display device based on the above-mentioned RGB image information may be divided into the field based on minimum/maximum/average of luminance, the field for adopting user's setting based on reference images, and the field for analyzing the histogram of luminance.
As an example of the first field, U.S. Pat. No. 6,795,053 discloses a technology for controlling the display light source based on brightness and contrast enhancement. As an example of the second field, U.S. Pat. No. 6,414,664 discloses a technology for expressing contrast in accordance with user's setting and controlling the display driving voltage.
The present invention belongs to the field for analyzing the histogram of luminance, and is to enhance the brightness and contrast and reduce the power consumption of a light source by extracting the image characteristic through such analysis.